Coarse separation and large-scale geometry of wreath products

Fuente: arXiv
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Main Authors: Bensaid, Oussama, Genevois, Anthony, Tessera, Romain
Format: Preprint
Published: 2024
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author Bensaid, Oussama
Genevois, Anthony
Tessera, Romain
author_facet Bensaid, Oussama
Genevois, Anthony
Tessera, Romain
contents In this article, we introduce and study a natural notion of coarse separation for metric spaces, with an emphasis on coarse separation by subspaces of polynomial or subexponential growth. For instance, we show that symmetric spaces of non-compact type different from $\mathbb{H}_\mathbb{R}^2$ and thick Euclidean buildings of rank $\geq 2$ cannot be coarsely separated by subspaces of subexponential growth; and that a connected nilpotent Lie group of growth degree $D \geq 2$ cannot be coarsely separated by a subspace of polynomial degree $\leq D-2$. We apply these results to the large-scale geometry of amalgamated free products and wreath products. The latter application is based on an Embedding Theorem that generalises previous work of the last two authors, and which is of independent interest. We also discuss some further applications to the distorsion of coarse embeddings between certain metric spaces.
format Preprint
id arxiv_https___arxiv_org_abs_2401_18025
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Coarse separation and large-scale geometry of wreath products
Bensaid, Oussama
Genevois, Anthony
Tessera, Romain
Group Theory
Metric Geometry
20F65, 20F69
In this article, we introduce and study a natural notion of coarse separation for metric spaces, with an emphasis on coarse separation by subspaces of polynomial or subexponential growth. For instance, we show that symmetric spaces of non-compact type different from $\mathbb{H}_\mathbb{R}^2$ and thick Euclidean buildings of rank $\geq 2$ cannot be coarsely separated by subspaces of subexponential growth; and that a connected nilpotent Lie group of growth degree $D \geq 2$ cannot be coarsely separated by a subspace of polynomial degree $\leq D-2$. We apply these results to the large-scale geometry of amalgamated free products and wreath products. The latter application is based on an Embedding Theorem that generalises previous work of the last two authors, and which is of independent interest. We also discuss some further applications to the distorsion of coarse embeddings between certain metric spaces.
title Coarse separation and large-scale geometry of wreath products
topic Group Theory
Metric Geometry
20F65, 20F69
url https://arxiv.org/abs/2401.18025